territorial chickens

After Removing Robert the rooster from our little family we purchased two point of lay chickens same breed as Lulu and Tiny just abit more white on them.

Anyway Lulu seems ok around them but any chance Tiny gets she chases after them and pecks them, poor Daisy and Pebbles spend all day hiding behind the bushes while Lulu and Tiny roam the backyard. Late afternoon they all get put to bed (Their coop is a large greenhouse which doesnt get used) Lulu and Tiny sleep down the far end up on their roost - also a sheltered area and Daisy and Pebbles sleep in the middle or towards the door on their roost but it is not under complete cover, I tried putting them down the back with the other two - on the other side but Tiny keeps chasing them away.

Just a bit worried that when they start laying they might get chased out of the nesting boxes as well.

Is there anyway that I can get Tiny and Lulu to be civil to their adopted sisters??